Premier Peter Gutwein announced on Monday the wide-ranging commission of inquiry would begin in early 2021 and run for a year.

It was revealed last week three staff at Ashley Youth Detention Centre had been stood down amid allegations of historical abuse including rape.

Mr Gutwein said he was briefed on Friday of further alleged cases of historical abuse involving a male teacher, who has been stood down and charged, from a northern school

He said a mental health services staff member had also been stood down over historical sex abuse allegations outside of work which are subject to criminal proceedings.

"My message to survivors is the commission of inquiry will provide that opportunity to come forward," Mr Gutwein said.

"This is our opportunity once and for all to deal with the matter and, as we move forward, to make sure our children are safe."

The state government has been under pressure to set up an inquiry after historical sex abuse allegations against a nurse were recently revealed.

It is alleged James Griffin, who died by suicide aged 69 in late 2019 not long after being charged, abused girls over a period from the 1980s to early 2010s.

In estimates hearings on Monday health department secretary Kathrine Morgan-Wicks said three of Griffin's patients had been identified in child exploitation material found at his house.

Mr Gutwein said the commission of inquiry would combine existing investigations and complement the national redress scheme which is expected to receive 2000 claims from survivors in Tasmania.

A commission of inquiry has the power to compel witnesses to give evidence.

The probe's terms of reference will be drawn up over coming weeks, Mr Gutwein said.

State opposition parties and the children's commissioner have backed the announcement.

Australian Associated Press